Flagella of the unicellular green alga Chlamydomonas are being studied to determine the functions of the individual flagellar components in the control and coordination of flagellar movement, and to learn more about the mechanisms involved in axonemal assembly and the control of flagellar growth. Chlamydomonas mutants having impaired motility are being analyzed by electron microscopy, gel electrophoresis and enzymatic analysis in order to correlate defects in flagellar function with missing axonemal structures or proteins. The various ATPases of the flagellum are being isolated and characterized, and their locations and functions within the flagellum are being investigated. Fine structural studies are being carried out to correlate changes in outer doublet arm conformation with the steps of nucleotide binding and hydrolysis in the mechanochemical cycle of dynein. Studies are in progress to identify a Ca++-binding axonemal component involved in the control of flagellar wave symmetry. The times and rates of synthesis of individual axonemal proteins, their times of transport into the flagellum during flagellar regeneration, and whether they undergo processing during their assembly into the axonemal superstructure are being investigated.